Investigating Mitochondrial Genome Dynamics in Plants

The plant mitochondrion represents a wonderfully multifarious and dynamic cellular compartment that directs processes associated with energy metabolism, cell stress responses, several biosynthetic functions, and ultimately programmed cell death. In higher plants, the genetic information contained within the mitochondrial compartment is organized in a multipartite, highly redundant configuration such that relative copy number of various DNA molecules can vary dramatically. The process of copy number shifting within the plant mitochondrial genome is the subject of this project. Experimental approaches are directed at determining the differences in the organization of mitochondrial genetic information that is inherited and mitochondrial genetic information that is contained in the vegetative tissues of the developing plant. Likewise, investigations are focused on the nature of the genome structure that allows dramatic copy number changes to occur. Because this laboratory has already cloned a nuclear gene that directs the copy number shifting phenomena in plant mitochondria, CHM, it should be possible to deduce the role of this gene by characterizing mitochondrial genome shifting processes. This research is likely to have implications not only for the manipulation of the mitochondrial genome in crop improvement and hybrid seed production, but also in deducing processes involved in mitochondrial inheritance, an area of great interest in human genetics as well.